The present invention relates to an apparatus for filling containers, and more particularly, to a microfiltrated clean air supply system for a filling machine. The microfiltrated clean air supply system provides high volume, substantially particle-free air flow to the filling machine. The clean air supply system uses sets of relatively less expensive filters to advantageously provide a clean air supply to the filling machine.
Current packaging machines integrate various components necessary to fill and seal a container into a single machine unit. Such a packaging machine is used to perform a packaging process, which generally stated, includes feeding carton blanks into the machine to form cartons, sealing the bottom of the cartons, filling the cartons with the desired contents, sealing the tops of the cartons, and then off-loading the filled cartons for shipping.
Trends within the field of packaging machines point toward increasingly high capacity machines capable of rapid, continuous filling and sealing of a very large number of identical or similar packaging containers, e.g., containers of the type intended for liquid contents such as milk, juice, and the like. One such machine is disclosed in U.S. Pat. No. 5,488,812, issued Feb. 6, 1996, and entitled "Packaging Machine." The machine disclosed in that patent includes a plurality of processing stations, each station implementing one or more processes to form, fill, and seal the containers. Each of the processing stations is driven by one or more servomotors that drive the various components of each of the processing stations.
Another type of packaging machine is exemplified by the TR/7.TM. and TR/8.TM. packaging machines manufactured and available from Tetra Pak, Inc. Such machines are of a more conventional type in which many of the components are driven from a common drive motor through, for example, indexing gears and cam mechanisms.
Problems also occur in known filling machines having clean air supply systems. For example, certain machines have possible recontamination and recirculation problems as a result of not providing point of use delivery. Another problem is that known clean air systems do not provide the filters with adequate protection from product spills or other liquid splashes. Such known systems typically include blowers and HEPA filters located above the conveyor line of containers to be filled. Perforated metal diffuser plates are typically arranged beneath the filters. However, these systems do not provide adequate protection from product or other liquid splashes. Similarly, a related problem is that certain known clean air systems are not cleanable by automatic methods and equipment. As a result, the clean air systems can act as recontamination sites.
Currently, known filling and packaging machines utilize clean air systems having filters for cleaning the incoming ambient air to subsequently provide a clean air supply to the filling machine. Certain filling machines use what are known as "absolute" membrane-style filters. These filters are quite expensive, have utilities consumption costs, require substantial ancillary equipment including compressor pumps, and have relatively low throughput capacity. As a result of the high initial cost of these systems, as well as the maintenance costs, and utilities consumption costs, for a clean air supply system used on a filling machine or other apparatus is directly increased. A filtered air system in which less costly filters could be used, while still yielding a comparable collection efficiency is currently needed. In addition, a filtered air system having reduced utilities consumption costs and increased capacity is needed.